Field of the Invention
This invention pertains to an apparatus characterized by a bundle of chalcogenide fibers coupled to a detector.
Description of Related Prior Art
Infrared spectroscopy is a powerful procedure for the study of not only chemical compounds but also their relationship to surrounding molecules. Its application to tissues has been hampered by problems in sample preparation for optimal spectra acquisition and the strong absorption of infrared light by water. By resolving technical and methodological problems, it is possible to apply infrared spectroscopy to the study of human and other tissues. Thus, it is possible to demonstrate that the spectra of cancerous flesh tissues are significantly different from those of corresponding non-cancerous tissues.
Other problems of the prior art generally relate to the large size of fibers employer which made the use of a fiber bundle impractical for remote in-vivo biomedical imaging.
The article entitled "Recent Advances And Trends in Chalocogenide Fiber Technology: A Review" by Nishii et al in the Journal of Non-Crystalline Solids, 140 (1992), pp. 199-208, discloses certain aspects pertinent herein. The Nishii article discloses that infrared fiber radiometry enables one to monitor the temperature and obtain thermal images in a restricted space without interference from electromagnetic waves, microwaves, etc. The Nishii et al article discloses preparation of sulfide, selenide and telluride glass fibers for infrared optical applications. In col. 2 on p. 206 of the Nishii et al article, disclosed is a coherent fiber bundle 100 cm long with 1386 AsS fibers of 55 microns core diameter and 75 microns outside diameter of a Teflon .RTM.) polymer cladding arranged in a hexagonal geometric pattern. Thickness of the cladding of course, was 10 microns. The fibers were arranged in rectangular pack of dimensions 2.8.times.3.4 mm. The fiber bundle was connected to an infrared television camera AVIO TVS-2100. The detector in the camera was an InSb crystal having sensitivity in the wavelength region between 3.0 and 5.4 microns. ZnSe and Si lenses were attached at the ends of the fiber bundle. FIG. 10 in the article shows thermal images of an operating integrated circuit delivered through the fiber bundle and directly detected by the camera.
The Yamagishi et al article entitled "IR Transmission Chalcogenide Glass Fibers", obtained about 1992, also describes certain aspects pertinent herein. The Yamagishi article also describes preparation of several chalcogenide fibers with Teflon polymer and glass cladding. The Yamagishi article discloses under the heading "Temperature monitoring and thermal imaging" a coherent AsS fiber bundle 100 cm. long with 8400 fibers, with the fibers having As S cores of 65 microns diameter and Teflon polymer cladding of 75 microns outside diameter. Based on these figures, the cladding thickness was 5 microns. The fibers were arranged in a hexagonal geometric pattern and arranged in a rectangle of dimensions 5.times.7 mm held together only in the vicinity of the fiber ends by an adhesive. A regular array of the fibers was achieved by controlling the fiber diameter to within .+-.2 microns. The fiber bundle was connected to an infrared television camera AVIO TVS-2100, with a detector of the In Sb crystal, having peak sensitivity in the wavelength region between 3 microns and 5.4 microns. The performance of the system was estimated by detecting the thermal image of an operating integrated circuit. A thermal image as low as 25.degree. C. could be delivered clearly through the fiber bundle.
The article "Chalcogenide fiber bundle for 3D spectroscopy" by Suto in Infrared Physics and Technology, 38 (1997) 93-99, has the following Abstract: "A fiber bundle is fabricated for use in three-dimensional spectroscopy. The bundle has 100 fibers with chalcogenide glass cores (AsS) whose shape of the cutting surface is square. The fibers are arrayed 10.times.10, and 1.times.100 on the input and output side, respectively, whereby two-dimensional images are reformatted into a linear array. The output beams from fibers are dispersed by a grating and their spectra are detected simultaneously on a two-dimensional photo-detector. Preliminary results obtained by our fiber bundle are presented here."